Critics of Turkey's president across Europe tell of threats

Ercan Karakoyun looks twice over his shoulder when he leaves his Berlin home to make sure nobody is following him.

Karakoyun is a follower of Muslim cleric Fethullah Gulen, whom Turkish President Recep Tayyip Erdogan blames for an attempted military coup in Turkey last summer. The 37-year-old, who is the public face of the Gulen movement in Germany, says he has received several death threats since the aborted overthrow.

The hostility hasn't escalated past the anonymous threats, but Karakoyun's experience is one happening across Europe as Turkey's government tries to root out and punish the U.S.-based Gulen's supporters both within Turkey and abroad.